The present invention is directed to a guide and tensioning device for endless track vehicles and more specifically to an adjustable spring-biased support plate for a sprocket over which an endless track is entrained.
In endless track vehicles of the type used for off the road construction equipment such as bulldozers and the like, each endless track is usually entrained about a pair of large diameter sprockets with one of the sprockets being a drive sprocket and the other sprocket being an idler sprocket. The sprockets are generally mounted for rotation on an elongated support assembly secured to the body of the vehicle and extending along a side thereof. In order to properly tension the endless track about the sprockets, the idler sprocket is usually provided with some type of adjustment relative to the support plate. However, such an adjustment of the sprocket relative to the support assembly is generally difficult to accomplish and involves raising the vehicle so as to remove all weight from the endless track and sprockets. Furthermore, such adjustment arrangements are generally designed to rigidly secure the idler sprocket to the support assembly at the desired distance from the drive sprocket.
In addition to providing support for the drive sprocket and the idler sprocket, the support assembly also is used to support a plurality of idler rollers intermediate the sprockets to prevent the endless track from being forced upwardly between the sprockets as the vehicle passes over rough and uneven terrain and to prevent sagging of the endless track between the sprockets due to the weight of the track. Such idler rollers are generally mounted on shafts which extend through the support assembly with guide rollers mounted on opposite sides of the support assembly. Such an arrangement however, results in a wider support assembly for the endless track thereby unduly increasing the overall width of the endless track vehicle.